Ce4+与RE3+的氟化物绿色分离方法

我国拥有得天独厚的稀土资源 ,已探明的稀土资源 (按氧化物ＲＥＯ计 )占全球稀土总量 80 %。然而 ,我国的稀土工业仍未摆脱资源利用率低和污染严重的困境 ,稀土资源的优势效应仍没有凸显出来。因此 ,稀土生产的绿色化[1] 对作为ＷＴＯ新成员的我国意义十分重大。现行的稀土冶炼工艺包括由化学浸取、化学分离和化学纯化等一系列线性的非循环的化学反应。如硫酸复盐沉淀分离法是通过Ｎａ2 ＳＯ4 与ＲＥ2(ＳＯ4 ) 3形成复盐沉淀实现Ｃｅ4 +与ＲＥ3+的分离 ,然后加入ＦｅＳＯ4 还原Ｃｅ4 +为Ｃｅ3+,再形成复盐沉淀 ,使Ｃｅ3+脱离硫酸介质体系。…     

镧与L-酪氨酸和甘氨酸三元固态配合物的热化学研究

由于稀土元素镧与氨基酸形成的配合物具有抗癌、抗肿瘤活性 ,人们对稀土氨基酸配合物的研究产生了浓厚兴趣。有关这类配合物的制备和表征的研究较多[1～ 4] ,而对其热化学性质的研究较少。我们按文献[5] 方法合成了配合物Ｌａ(Ｔｙｒ)(Ｇｌｙ) 3Ｃｌ3·3Ｈ2 Ｏ(ｓ) ,在自行研制的具有恒定温度环境反应热量计上 ,分别测定了Ｌａ2 Ｏ3(ｓ)、氨基酸 [Ｌ 酪氨酸 (Ｌｙｒ) +甘氨酸 (Ｇｌｙ) ]和配合物在2ｍｏｌ·Ｌ- 1 ＨＣｌ溶液中的溶解焓 ,通过设计的热化学循环得出配合反应焓 ,进而计算出Ｌａ(Ｔｙｒ)(Ｇｌｙ) 3Ｃｌ3·3Ｈ2 Ｏ(ｓ)的标准摩尔…     

掺杂Eu~(3+)的Na_(24)As_2Mo_(22)O_(83)的合成及其发光特性

本文在固相合成掺杂稀土离子的单钨酸盐、混合碱土金属钨酸盐[1～ 3 ] 等体系的系统研究基础上 ,采用固相反应法合成掺杂Ｅｕ3 + 离子的Ｎａ2 4Ａｓ2 Ｍｏ2 2 Ｏ83 荧光体结晶粉末 ,并经元素分析 ,ＩＲ和Ｘ射线粉末衍射等分析手段确定了它的结构 ,探讨了Ｅｕ3 + 离子在Ｎａ2 4 Ａｓ2 Ｍｏ2 2 Ｏ83 中的发光和能量传递机理。1　实验部分1 1　试剂及样品的制备先将Ｎａ3 ＡｓＯ4 ·1 2Ｈ2 Ｏ (分析纯 )和Ｎａ2 ＭｏＯ4 ·2Ｈ2 Ｏ(分析纯 )在 2 5 0℃下灼烧 30ｍｉｎ脱水制得Ｎａ3 ＡｓＯ4 和Ｎａ2 ＭｏＯ4 结晶粉末 ,再按一定物质的量比 ( 9…     

合成沸石用溶液组分的中间控制分析

沸石是天然和合成水合钠 (钾、钙、钡 )铝硅酸盐矿物的通称。合成沸石基于铝硅酸盐外配位层和沸石分子中碱 (碱土 )金属、铝、硅之间摩尔比的不同以及合成条件的差异 ,而有多种型号。其中常用的Ｎａ Ａｌ Ｓｉ结构框架的就有 4Ａ、 13Ｘ、Ｙ、丝光沸石等类型[1] ,而 4Ａ沸石经ＫＣｌ或ＣａＣｌ2 部分交换处理后 ,生成 3Ａ (Ｋ Ｎａ Ａｌ Ｓｉ)或 5Ａ (Ｃａ Ｎａ Ａｌ Ｓｉ)沸石 ;13Ｘ型 (Ｎａ Ａｌ Ｓｉ)经ＣａＣｌ2 交换后生成10Ｘ (Ｃａ Ｎａ Ａｌ Ｓｉ)沸石。因此 ,Ｎａ Ａｌ Ｓｉ型合成沸石是制取其它合成沸石的基础。本文介绍的合成沸…     

四元交互体系Li~+,K~+/Cl~-,CO_3~(2-)-H_2O在298K时相平衡及物理化学性质研究

位于我国西藏腹地的扎布耶盐湖 ,是世界上罕见的富含锂、钾等碱金属和富含硼的碳酸盐 硼酸盐的特种盐湖 .该湖卤水主要由Ｌｉ+,Ｎａ+,Ｋ+,Ｃｌ- ,ＣＯ2 -3 ,ＳＯ2 -4 ,Ｂ4Ｏ2 -7,ＨＣＯ-3 等物种构成 .显然 ,开展该湖卤水体系的理论和实验相平衡研究 ,不仅对该种类型盐湖卤水的成因和成矿规律、对于这类复杂水盐体系化学行为的理论和实验描述研究具有重要意义 ,而且对于该盐湖卤水盐类资源综合利用方案的制定具有指导意义 .但是 ,迄今为止 ,除陈郁华[1 ] 报道过关于 2 98Ｋ条件下该湖卤水体系等温蒸发实验研究的结果外 ,尚未见到关于该湖卤…     

离子液体[C2mim][GaCl4]的溶解热研究

在干燥氩气氛下, 用等摩尔的高纯无水GaCl3和[C2mim][Cl](氯化1-甲基-3-乙基咪唑)直接搅拌混合, 制备了淡黄色透明的的离子液体[C2mim][GaCl4] (1-ethyl-3-methylimidazolium chlorogallate) . 在298.15 K下, 利用具有恒温环境的溶解反应热量计, 测定了这种离子液体的不同浓度摩尔溶解焓 . 针对[C2mim][GaCl4]溶解于水后即分解的特点, 在Pitzer电解质溶液理论基础上, 提出了确定这种离子液体标准摩尔溶解焓的新方法, 得到了[C2mim][GaCl4]在水中的标准摩尔溶解焓, ＝－132 kJ•mol－1, 以及Pitzer焓参数组合: ＝－0.1373076和 ＝0.3484209. 借助热力学循环和Glasser离子液体晶格能理论, 用Ga3＋, Cl－和[C2mim]—的离子水化焓数据以及本文得到的[C2mim][GaCl4]标准摩尔溶解焓, 估算了配离子4Cl－(g)解离成Ga3＋(g)和4Cl－(g)的解离焓ΔHdis([GaCl4]-)≈5855 kJ•mol－1. 这个结果揭示了离子液体[C2mim][GaCl4]的标准摩尔溶解焓绝对值并不很大的原因, 即是很大的离子水化焓被很大的[GaCl4]－(g)的解离焓相互抵消了.     

Na~+,K~+,Mg~(2+)//Cl~-,SO_4~(2-)-H_2O五元体系15℃介稳相图研究

得到Ｎａ＋,Ｋ＋,Ｍｇ２＋//Ｃｌ－,ＳＯ_４_(２－)－Ｈ２Ｏ五元体系１５℃时的介稳溶解度数据,绘制了该体系１５℃的介稳相图,共有９个为氯化钠所饱和的结晶区域:氯化钾、硫酸钠、钾钠芒硝、软钾镁矾、白钠镁矾、光卤石、七水硫酸镁、六水硫酸镁和水氯镁石．所得１５℃介稳相图和Ｖａｎ'ｔ Ｈｏｆｆ稳定相图比较有较大区别;在１５℃介稳相图中钾镁矾、钾盐镁矾以及五水硫酸镁和四水硫酸镁结晶区域消失,而软钾镁矾结晶区域显著扩大．比较作者所作该五元体系１５℃,２５℃及３５℃介稳相图,发现软钾镁矾(包括钾镁矾)相区以２５℃时最大,３５℃时最小;随温度升高,钾钠芒硝结晶相区依次向ＫＣｌ相区平行移动,导致ＫＣｌ相区缩小,Ｎａ２ＳＯ４相区扩大;随温度升高相应点的钠含量和水含量依次减小．     

Crystal Structure of Complex （Et4N）[VFe3S4Cl3（CH3CN）3]

1　ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅ1980,ｍａｎｙＶ/Ｆｅ/Ｓｈｅｔｅｒｏｍｅｔａｌｌｉｃｓｕｌｆｕｒｃｌｕｓｔｅｒｃｏｍｐｏｕｎｄｓｈａｖｅｂｅｅｎｒｅｐｏｒｔｅｄ.ＲａｕｃｈｆｕｓｓｅｔａｌｏｂｔａｉｎｅｄｔｗｏｋｉｎｄｓｏｆＶ/Ｆｅ/Ｓｃｏｍｐｏｕｎｄｓ[1]ｕｓｉｎｇ(ＣＨ3Ｃ5Ｈ4)2Ｖ2Ｓ4ａｓａｎｏｒｇａｎｏｍｅｔａｌｌｉｃｌｉｇａｎｄ,ｏｎｅｉｓ(ＭｅＣｐ)2Ｖ2Ｆｅ2(ＮＯ)2Ｓ4ｗｉｔｈａｃｕｂａｎｅｌｉｋｅｓｔｒｕｃｔｕｒｅａｎｄａｎｏｔｈｅｒｉｓ(ＭｅＣｐ)2Ｖ2Ｓ4Ｆｅ(ＮＯ)2ａｎｄ(ＭｅＣｐ)2Ｖ2Ｓ4…     

过渡金属离子液体[C2mim][FeCl4]的溶解热

在干燥氩气氛下, 用等摩尔的高纯无水FeCl3和氯化1-甲基-3-乙基咪唑([C2mim][Cl])直接搅拌混合, 制备棕色透明的含过渡金属铁的离子液体[C2mim][FeCl4]. 在298.15 K下, 利用具有恒温环境的溶解反应热量计测定了这种离子液体的摩尔溶解焓(ΔsHm). 针对[C2mim][FeCl4]溶解于水后即分解的特点, 在Pitzer电解质溶液理论基础上, 提出了确定这种离子液体标准摩尔溶解焓的新方法, 得到了[C2mim][FeCl4]的标准摩尔溶解焓(ΔsH 0—m=-76.6 kJ/mol), 以及Pitzer焓参数组合: β(0)LFe,Cl+β(0)L[C2mim], Cl+ΦLFe,[C2mim]=0.072209和β(1)LFe,Cl+β(1)L[C2mim], Cl=0.15527. 借助热力学循环和Glasser离子液体晶格能理论, 用Fe3+, Cl-和[C2mim]+的离子水化焓数据以及[C2mim][FeCl4]标准摩尔溶解焓, 估算得到了配离子[FeCl4]-(g)解离成Fe3+(g)和4Cl-(g)的解离焓为5659 kJ/mol. 这个结果揭示了离子液体[C2mim][FeCl4]的标准摩尔溶解焓绝对值并不很大的原因, 即很大的离子水化焓被很大的[FeCl4]-(g)的解离焓相互抵消.     

K2CaB8O26H24单晶结构和溶解转化机理

本研究报道K2CaB8O26H24复盐单晶的X射线衍射结构测定结果。结构式为K2Ca[B4O5(OH)4]2·8H2O,属正交晶系(orthorhombic),空间群P212121,晶胞参数a=1.1550(2)nm,b=1.2484(2)nm,c=1.6580(2)nm。分子体积V=2.3906(6)nm^3,Z=4,Dc=1.792g·cm^-3,μ=0.720mm^-1,F=(000)=1320。使用振动光谱表征了该复盐的基团特征。根据该复盐在水中的溶解过程,讨论了溶解转化机理,得出该复盐为组分不同步溶解,溶解产物属于无定形态,后转化为晶态Ca[B3O3(OH)5]·4H2O.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.